In tuto sympa surserde (parce que autant les fonctionnalités de serde-derive sont ergonomiques et plutôt bien documentées, autant la partie manuelle c'est moins évident.

Edit: sur serde-derive Mick m'a appris ça:

#[serde(try_from = "&[u8]")]
pub struct Signature(
    #[serde(serialize_with = "<[_]>::serialize")] [u8; LENGTH],

Comme serde ne supporte pas les const-generics il est limité aux tableaux de 32 éléments de long, mais l'invocation du dessus permet de contourner le problème:

serde does not support const generics yet and so ser/deser is only implemented for [T; N] where N <= 32.

try_from uses a TryFrom implementation to deserialize.

serializewith = "<[]>::serialize" uses the slice serialization implementation instead of the fixed length array.

Ubuntu Image-Hardening.

1. Disable the root login.
2. Change the default SSH port
3. Replace password authentication with SSH keys.
4. Enable AppArmor
5. Enable the Firewall
6. Update Everything
7. Remove Unused Packages
8. Run Regular Backups
9. Install fail2ban
10. Ensure Only root Has UID of 0
11. Secure Shared Memory
12. Disable all unnecessary ports
13. Enable SYN cookie (unless it conflicts/interferes with cloud services)

# show the swap file in your system.
swapon --show
# turn the swap off. You should also make sure that you have enough free RAM available to take the data from swap file.
sudo swapoff /swapfile
# change the size of the swap file.
sudo fallocate -l 20G /swapfile
# mark this file as swap file:
sudo mkswap /swapfile
# enable the swap file
sudo swapon /swapfile
# see the result
swapon --show

I think it's an entirely reasonable pattern to accept impl Into<Option<T>>, so that you can pass None or t without having to pass Some(t).